Water has become increasingly recognized as an important natural resource of limited availability in some geographical areas making conservation measures desirable.
The conventional water closet includes a water storage tank, a waste receipt bowl and passageways for creating siphoning or jet action by the rapid release of water from the water storage tank. Traditionally such water closets have been designed to empty the entire contents of the water tank each time the flushing actuator is operated. However, it is now known that less than the entire water contents of the tank is needed to adequately purge the waste receiving bowl of liquid wastes and refill it with clean water. Usually, however, the entire water content of the tank is needed for removal of solid wastes.
A large variety of devices have been suggested for conserving water in the flushing operation. Some, such as the device illustrated in my earlier U.S. Pat. No. 4,145,774, have two selectable modes of operation. In one mode a flush is initiated which utilizes all of the water in the tank. In the other mode a flush is initiated which uses only part of the stored water. Other types of devices have only one mode of operation in which less than the entire tank volume is utilized.
One popular type of discharge valve closure is the type shown in U.S. Pat. No. 4,028,748. It has a unitary molded body forming the sealing portion, which sealingly engages the valve seat of the discharge valve, and a buoyancy chamber which extends downwardly and has a drain hole at the bottom. When such a conventional discharge valve closure is in the closed position, water drains from the buoyancy chamber. When the valve is lifted by operation of the actuating arm, it is buoyant and remains raised with the valve open until the water level lowers below the discharge valve thereupon permitting the discharge valve to fall by gravity back into the closed position upon the valve seat.
Similar operation is obtained by the valves shown in U.S. Pat. Nos. 2,741,775 and 2,598,967. These devices have no buoyancy chamber but instead rely upon a lightweight foam material for buoyancy.
Other inventors discovered that the conventional discharge closure of the type having a buoyancy chamber can be made to close prematurely, that is before the water level falls below the level of the discharge valve closure, by providing a smalll bleeder port in the buoyancy chamber above or below the sealing portion of the discharge valve closure. In those with the bleeder port above the seal, a snorkle extends upwardly above the water surface level of the filled tank.
In those with a bleeder hole below the seal, preferably the bleeder hole is formed so that it will be facing upwardly when the discharge valve closure is raised to its full open position.
These structures permit the escape of air from the buoyancy chamber so that water may enter the chamber and reduce the buoyancy of the closure to the point that the valve will fall closed before the entire tank contents has been exhausted through the discharge valve. Such structures are shown in U.S. Pat. Nos. 3,935,598; 3,969,775; 4,000,526; and 4,189,795.
Some of these types of devices permit no adjustment for controllably varying the rate of water inlet which determines the rate of change of the buoyancy of the closure and therefore determines the water level at which the discharge valve will fall closed. One device provides a float arrangement attached to the valve for adjustment purposes. Still others provide adjustment by a variety of structures for varying the orifice size by a type of a manually adjustable valve means. Others change the orifice size by providing a plurality of interchangeable inserts having orifices of different sizes. Ordinarily the size of the bottom drain hole is adjusted in the prior art units.
My prior U.S. Pat. No. 4,145,774 utilized a buoyancy chamber with a bleeder hole system but combined it with a unique bistable handle to give improved modes of operation.
It is desirable that an adjustment be provided for the discharge valve closures having a bleeder port in order to permit the adjustable selection of the water level at which the discharge valve closure will prematurely close. Such adjustment is desirable to compensate for variations in the tank structures of different toilet manufacturers, to compensate for the different needs of different sewage and water systems and to permit the owner to select the water volume which the owner desires to utilize when obtaining a reduced water volume flush.
However, the adjustment systems which have previously been suggested are difficult to adjust especially for peopel of limited dexterity or mechanical ability and are subject to the deposit of minerals and other materials which interfere with their operation. Additionally, it is not only more difficult for the owner but more expensive for the manufacturer to provide a plurality of interchangeable orifices or an adjustable orifice valve. Finally, orifices which are adjustable in size are more sensitive to the effect of deposition of materials which will further constrict the size of the orifice.
There is therefore a need for a discharge valve closure which can be adjusted for selection of the desired water level at which the valve will close which is simple, inexpensive and easy to manufacture and yet which does not require interchangeable parts or adjustable valves for adjusting the size of the orifices.